Smoking articles

Abstract: Smoking articles, cigarettes for example, having a tar delivery of not more than 6mg, a filter ventilation of at least 50% and a ventilation zone located not less than 75% of the length of the filter from the mouth end thereof exhibit enhanced mainstream smoke water-to-tar ratios.

Description: The subject invention relates to smoking articles. Smokers of low tar delivery cigarettes have reported that the mainstream smoke therefrom is of a dry character. Methods for improving the taste of low delivery ventilated cigarettes are known, for example the patent DE 4 118 815 discloses a triple filter for a cigarette wherein the triple filter comprises three sections, the central section of which has a central bore. The filter further comprises ventilation holes positioned upstream of the central section of the filter, such that the bore of the central section acts as a mixing chamber for the mixing of mainstream smoke and ventilation air prior to the smoke being inhaled by the smoker. It is an object of the subject invention to provide low tar delivery cigarettes which exhibit an enhanced mainstream smoke water-to-tar ratio. The subject invention provides a smoking article comprising a smoking material rod and a filter, the NFDPM delivery of the article being not more than about 6mg under standard machine smoking conditions, the filter being of a homogenous internal constitution, the filter being ventilated to at least a 50% ventilation value and the ventilation zone being located not less than 75% of the length of the filter from the mouth end thereof, whereby there is provided a smoking article which exhibits a mainstream smoke water-to-NFDPM ratio (x 100) of at least 6. Preferably, the ventilation level is at least 60%. It is also preferable that the ventilation zone is located not less than about 80% of the length of the filter from the mouth end thereof. Advantageously, the ventilation zone is located at least 20mm from the mouth end of the filter and it may be located 24mm or more from the mouth end. Advantageously, the filter is a mono-filter and is of, substantially at least, homogeneous internal constitution throughout its length. It may comprise as filtration material fibrous cellulose acetate tow. When cigarettes are smoked at standard (ISO) machine smoking conditions, the smoking machine takes a 35cc puff of 2 seconds duration in each minute. The degree of ventilation is taken to be the percentage of the 35cc puff volume which is constituted by ventilation air. As used herein the term "tar" means total particulate matter of the mainstream smoke less nicotine and water (NFDPM). It is measured according to a standard procedure at standard machine smoking conditions and with the use of a Cambridge filter pad. Preferably, the NFDPM delivery of smoking articles according to the subject invention is not more than about 5.5mg. It may be as low as 2 to 3mg. The ventilation of cigarettes according to the subject invention may be provided by mechanical, laser or electrostatic means and may take the form of a single row of holes extending circumferencially of the filter or of a wider zone of perforation openings. If such zone is of significant width, i.e. that dimension extending lengthwise of the filter, the air flow rate will be higher towards the side of the zone nearer the mouth end of the filter and lower towards the other end. In such case the distance of the zone from the mouth end of the filter is taken to be the distance taken from the mouth end to the effective ventilation mid-point, this latter being the location in the ventilation zone whereof the total ventilation air flow per unit time upstream of the location is equivalent to the total ventilation air flow per unit time downstream of the location. EXAMPLE Control cigarettes and cigarettes according to the subject invention had the following features in common. Tobacco: Virginia Tobacco Tobacco rod lengths: 67mm Filter type: Cellulose Acetate Mono-Filter Filter length: 27mm Ventilation type: On-Machine Laser : Single line Ventilation (%): 60% For the control cigarettes the ventilation line was located at 12mm from the mouth end of the filter, whereas for the cigarettes according to the subject invention the ventilation line was located at 25mm from the mouth end of the filter. The tar deliveries of the control and inventive cigarettes were 5.30 and 5.80 (mg/cigarette) respectively. The water deliveries were 0.25 and 0.43 (mg/cigarette) respectively. Thus, whereas the water-to-tar ratio (X100) of the control cigarettes was 4.70, that for the inventive cigarettes was 7.40. Smokers reported that the quality of the mainstream smoke of the inventive cigarettes was superior to that of the control cigarettes.

Claims: A smoking article comprising a smoking material rod and a filter, the NFDPM delivery of the article being not more than about 6mg under standard machine smoking conditions, the filter being of homogenous internal constitution, the filter being ventilated to at least a 50% ventilation value and the ventilation zone being located not less than 75% of the length of the filter from the mouth end thereof, whereby the smoking article exhibits a mainstream smoke water-to-NFDPM ratio (x 100) of at least 6. A smoking article according to Claim 1, wherein the NFDPM delivery thereof is not more than about 5.5mg. A smoking article according to Claim 2, wherein the NFDPM delivery thereof is not more than about 3mg. A smoking article according to Claim 1, 2 or 3, wherein said filter is ventilated to at least a 60% ventilation level. A smoking article according to any one of Claims 1 to 4, wherein said ventilation zone is located not less than about 80% of the length of the filter from the mouth end thereof. A smoking article according to any one of the preceding claims, said smoking article being a cigarette.

Inventors: WHITE PETER REX, WHITE, PETER REX
Applicants: BRITISH AMERICAN TOBACCO CO, BRITISH AMERICAN TOBACCO (INVESTMENTS) LIMITED
Application year: 1994
Main classification: A24D1
IPC codes: A24D1, A24D3